Fabrication of topologically complex three-dimensional microfluidic systems in PDMS by rapid prototyping

Area of Science:

• Microfluidics
• Materials Science
• Polymer Science

Background:

• Fabricating complex 3D microfluidic systems is challenging.
• Existing methods often lack the ability to create intricate, non-intersecting channel geometries.
• Poly(dimethylsiloxane) (PDMS) is a common material for microfluidic devices due to its biocompatibility and ease of fabrication.

Purpose of the Study:

• To introduce a novel fabrication method for creating topologically complex 3D microfluidic systems in PDMS.
• To demonstrate the capability of the method to produce intricate channel designs, including those with crossovers and complex structures.
• To enable the creation of advanced microfluidic devices with enhanced functionality.

Main Methods:

• The "membrane sandwich" method utilizes two-level photolithography and replica molding to create masters.
• PDMS prepolymer is cured between aligned masters, forming a thin membrane with molded channel structures.
• Sequential removal of masters and thermal curing allows for the transfer and sealing of the PDMS membrane without feature distortion.

Main Results:

• The method successfully fabricated topologically complex 3D microfluidic systems in PDMS.
• Demonstrated fabrication of a "basketweave" structure and a square coiled channel surrounding a straight channel.
• The technique allows for the creation of channels that cross over and under without intersecting, enabling knot-like structures.

Conclusions:

• The membrane sandwich method is a versatile and effective technique for fabricating complex 3D microfluidic systems.
• This method opens possibilities for designing and manufacturing novel microfluidic devices with unprecedented geometric complexity.
• The ability to create intricate, non-intersecting channels has significant implications for various microfluidic applications.